I think that the Linhof compendium shade is usable with the 2x3" Technika, but the bracket to attach it is not easy to find. On my Tech V 23b (the latest version), there is a screw hole on top of the front standard, which I am fairly sure is where the compendium shade would connect. I don't know if they made a smaller shade for the smaller camera, or if it is just the 4x5" shade with a different bracket. You might ask on lfphoto.info, and Bob Salomon, the US rep for Linhof, is likely to have an answer.
Other possibilities would by systems like the Lee shade system that attach to the lens, though with normal-wide lenses there could be mechanical issues with the shade bumping against the focus rail.